In the case of minimally-invasive interventional interventions in radiology, cardiology and neurosurgery, different interventional instruments are used, which can comprise for instance a balloon for extending a vessel, a stent for eliminating a vessel stenosis or a prosthesis etc. The positioning of an interventional instrument on a specific point in the body of a patient during the minimally-invasive intervention very frequently takes place using x-rays. Attempts are made here to work with as small an x-ray dose as possible so as to keep the patient's and medical personnel's radiation exposure to a minimum. The visibility of the interventional instrument is however becoming increasingly more difficult not only on account of the use of ever smaller x-ray doses but also since the materials used for the interventional instruments are becoming increasingly more transparent for x-rays and it is always preferred by the average patient.
For a successful intervention, an exact positioning of an interventional instrument on the provided point is however necessary. This is particularly difficult in interventional cardiology, since the target vessel point is generally constantly moving as a result of the heart beat and frequently has to be processed using rather unfavorable projection directions when recording the x-ray images for guiding and positioning the interventional instrument.